Stevie is a woman on a mission to stop the deadly marathon, known as the Buffalo Run, that claimed the life of her daughter a few years ago. The race takes place in the heart of Yosemite Valley, where genetically engineered buffalo run rampant, hungry for human flesh. Despite the danger, Stevie manages to enter the race, determined to put an end to the madness once and for all.
As she runs the race, Stevie battles both the ferocious buffalo and her own inner demons, haunted by the memory of her daughter's tragic death. But with each step, she becomes more determined to succeed, and put an end to this barbaric spectacle and the corrupt government elites who sanction it.